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In times of instant messaging, a small analog printer makes it way into the light, connecting people. It is meant to hang in a shared apartment, an office, or wherever you like and when a message arrives, it is meant to be seen by whoever sees it. No private hidden message, no hiding behind a smartphone screen and writing with one specific friend, no constant alert status, waiting for the next message.

LittleBigPrinter — the fax machine for millennials.

Send a message here → Messenger


If you like this project, please also check out my other project → FlipDot Communicator

Hardware Setup

I refactored this project from an Raspberry Pi to an ESP32, as this is more lightweight code and runs more stable.



What is needed to build the case and wall mount:

  • 230 ✕ 160 mm, 3 mm thick acrylic glass. You can find the laser file here: 00_case/laser.dxf
  • 12 M3✕10 mm screws (+ 2-3 additional ones for cutting threads)
  • 4 M3 nuts
  • 4 aluminium tubes, Ø5 mm (inside ~ Ø2.5mm to cut in a M3 thread)
  • A three core cable for power supply


Pin Setup

ESP32 Components
Vin Power Supply +
GND Power Supply -
5V LED Matrix +
GND LED Matrix -
GPIO 21 LED Matrix D
GPIO 22 LED Matrix C
GND Printer Serial GND
GPIO 19 Printer Tx
GPIO 18 Printer Rx


Flashing The ESP32

The software for the ESP32 is built using the Arduino IDE. You can find all the files here → LittleBigPrinter-Software/

Libraries to install

You will need to install these libraries for the code to work:

Flash the ESP32

Next, open the .ino file. Add your credentials to the credentials.h file. The placeholders are these ones:

#define FIREBASE_HOST ""

If you are not sure where to find the Firebase credentials, this stackoverflow question will help you.

Finally flash it onto the board. Now you should be all set up!


  • Implement multi printer usage (per IDs within the database)
  • Add a buzzer to acoustically inform about new messages
  • Add a RGB LED and button (or something completely different) to change the paper color entry